Autonomous or semi-autonomous vehicles such as are now beginning to appear on roadways can, just like vehicles that are manually controlled by an operator, develop minor systems faults that can impede the vehicle's operation, e.g., problems with vehicle sensors or the like. A risk in an autonomous or semi-autonomous vehicle is that a minor systems fault can develop into a more serious fault, preventing operation of the vehicle, and leaving an occupant stranded in a dangerous situation, e.g., at a remote rural location where assistance is difficult to obtain, in the middle of a congested highway at rush hour, etc. Another risk in an autonomous vehicle is a possible inability to operate if environmental conditions change, e.g., when the autonomous vehicle approaches an area of bad weather, severe traffic, etc.